Overturning and rollover characteristics of a tractor through dynamic simulations: Effect of slope angle and obstacles on a hard surface

Abstract

The lateral overturning and backward rollover characteristics of a tractor driven on a hard surface were analysed depending on the ground slope angle and the shape and height of obstacles. The size and material properties of a tractor were used to create a 3D simulation model using a commercial dynamic simulation program. The simulation model was verified using tractor certification test results. For the simulations, ground slope was set to a maximum of 50° and four heights were applied to three different shapes of obstacle. Tractor driving speeds at which lateral overturning and backward rollover occurred were determined using each condition. The results revealed that the factor that contributed the most to the overturning and rollover of the tractor was ground slope, followed by the obstacle height and then obstacle shape. As the obstacle height and ground slope increased, the tractor became vulnerable to lateral overturning and backward rollover based on the height of its centre of mass and angular velocity in the rolling direction. Backward rollover occurred when the slope was mild and lateral overturning occurred above a certain slope angle. Depending on the obstacle shape, the sensitivity to lateral overturning and backward rollover varied with sinusoidal-shaped obstacles making the tractor relatively vulnerable to lateral overturning, whereas rectangular obstacles made it vulnerable to backward rollover. Therefore, on steep slopes, where lateral overturning occurs, sinusoidal-shaped obstacles are more risky, whereas on flat ground, where backward rollover occurs, rectangular obstacles are more risky. • Lateral slope angle and obstacle shape selected as main influencing factors. • Comprehensive analysis conducted on impact of slope angle and obstacle. • Three different obstacle shapes used: rectangular, right-triangular, and sinusoidal. • Ground slope maximum 50° and obstacle height maximum of 400 mm. • Speed of the tractor when overturning and rollover occurred determined.